DEVELOPMENT OF BACTERIOCIN-BASED BIOPRESERVATIVE FOR EXTENDING SHELF LIFE OF MILK AND MILK PRODUCT

Milk and traditional milk-based products are highly susceptible to microbial spoilage due to their rich nutrient composition and high moisture content. The demand for safe and natural preservation methods has increased interest in bacteriocins as potential biopreservatives. The present study aimed to develop and evaluate a bacteriocin-based preservation system for extending the shelf life of milk and a traditional milk product, barfi. Bacteriocin-producing strains including Lactobacillus rhamnosus, Bacillus clausii, and Bacillus coagulans were screened for antimicrobial activity. Crude bacteriocins were extracted and partially purified using ethyl acetate. Among the tested strains, L. rhamnosus showed significant inhibitory activity against selected foodborne pathogens. Minimum Inhibitory Concentration (MIC) analysis confirmed its effectiveness at relatively low concentrations. Protein estimation was carried out using the Folin–Lowry method. Application studies in milk and barfi demonstrated that bacteriocin treatment effectively delayed microbial growth and reduced spoilage. Microbiological and physicochemical parameters such as total viable count, coliform count, pH, titratable acidity, and Methylene Blue Reduction Test (MBRT) indicated improved stability in treated samples compared to controls. Incorporation of bacteriocin into a bioactive coating also contributed to extended shelf life in barfi. The findings suggest that bacteriocin from L. rhamnosus has promising potential as a natural biopreservative for milk and milk-based products.